Raspberrypi screen on and off toggle

lib/src/proxmox_lister/proxmox_lister_list_view.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:pi_dashboard/src/proxmox_webservice/model.dart';
 import 'package:pi_dashboard/src/proxmox_webservice/service.dart';
+import 'package:pi_dashboard/src/screen_helper.dart';
 import 'package:pi_dashboard/src/settings/settings_controller.dart';
 import 'package:pi_dashboard/src/settings/settings_service.dart';
 import '../settings/settings_view.dart';
@@ -72,6 +73,12 @@ class _ProxmoxListerState extends State<ProxmoxListerView> {
         appBar: AppBar(
           title: const Text("Proxmox VMs"),
           actions: [
+            IconButton(
+              icon: const Icon(Icons.nightlight),
+              onPressed: () {
+                toggleScreen();
+              },
+            ),
             IconButton(
               icon: const Icon(Icons.sync),
               onPressed: () {

lib/src/screen_helper.dart

@@ -0,0 +1,34 @@
+import 'dart:io';
+
+const _off = "1";
+const _on = "0";
+
+Future<void> toggleScreen() async {
+  if (await isScreenOff()) {
+    turnOncreen();
+  } else {
+    turnOffScreen();
+  }
+}
+
+Future<void> turnOffScreen() async {
+  await setBlFile(_off);
+}
+
+Future<void> turnOncreen() async {
+  await setBlFile(_on);
+}
+
+File blFile() {
+  return File("/sys/class/backlight/10-0045/bl_power");
+}
+
+Future<bool> isScreenOff() async {
+  final status = await blFile().readAsString();
+  if (status.startsWith(_on)) return false;
+  return true;
+}
+
+Future<void> setBlFile(String content) async {
+  await blFile().writeAsString(content);
+}